bla , a new chromosome-encoded bla -like variant in Shewanella sp. from the aquatic environment in Myanmar.

Shewanella sp., the progenitors of bla -like genes are increasingly reported with the possession of different bla -like variants. This study aims to characterize bla , a new variant of a bla -like gene identified in Shewanella sp. isolated from the aquatic environment in Myanmar. Phylogenetic analysis of the bla sequence with other bla -like variants showed that it has the highest nucleotide identity of 86.09% with bla . However, the active site motifs in OXA-731 were 100% identical to that in OXA-48. Whole-genome sequencing analysis showed that bla is not surrounded by any mobile genetic elements. The genetic context of bla was found as similar to other bla -like genes previously identified in Shewanella sp. S1 nuclease pulsed-field gel electrophoresis followed by Southern blotting confirmed the location of bla in the chromosome of the Shewanella genome. Cloning and expression studies showed that OXA-731 has β-lactamase activity similar to OXA-48 and OXA-181, but it has no significant carbapenemase activity. Our results showed the significance of bla -like-carrying Shewanella sp. in the spreading of bla -like genes in the community.